which of the following pairs of equations are perpendicular

Answer:

Đổi 60% = 3/5

a) Số học sinh trung bình là:  40 * 1/4 = 10 (hsinh)

Tổng số hsk và hsg là:  40 - 10 = 30 (hsinh)

Số học sinh khá bằng 60% số học sinh còn lại nên số hsk là:

             30 * 60% = 18 (hsinh)

Số học sinh giỏi là:  30 - 18 = 12 (hsinh)

b) Tổng số hs khá và giỏi chiếm số phần trăm trong lớp là:

             30 : 40 * 100 = 75%

Answer:

good question

but I don't know

please I am so sorry

Answer:

[tex]13\ units[/tex]

Step-by-step explanation:

One is asked to find the distance between two points on a coordinate plane. The easiest way to do so is to use the distance formula, this formula is the following:

[tex]D=\sqrt{(x_1-x_2)^2+(y_1-y_2)^2[/tex]

Where ([tex](x_1,y_1)[/tex]) and ([tex](x_2,y_2)[/tex]) are the points which one needs to find the distance between. In this case, these points are as follows:

[tex]k\ (-3,5)[/tex]

[tex]j\ (-8, -7)[/tex]

Substitute these points into the formula and solve for the distance between these points,

[tex]D=\sqrt{(x_1-x_2)^2+(y_1-y_2)^2[/tex]

[tex]D=\sqrt{((-3)-(-8))^2+((5)-(-7))^2[/tex]

Simplify,

[tex]D=\sqrt{((-3)-(-8))^2+((5)-(-7))^2[/tex]

[tex]D=\sqrt{(-3+8)^2+(5+7)^2[/tex]

[tex]D=\sqrt{(5)^2+(12)^2[/tex]

[tex]D=\sqrt{25+144}[/tex]

[tex]D=\sqrt{169}[/tex]

[tex]D=13[/tex]

Answer:

A≈706.86

Step-by-step explanation:

welcome to brainly

Answer:

Let π =22/7

area of circle = πr²

= 706.86

Step-by-step explanation:

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Answer:

3 chocolate bars and 2 graham crackers

Step-by-step explanation:

8 times 3 equals 24

12 times 2 equals 24

Answer:

Hello,

[tex]\begin{bmatrix}\dfrac{-1}{5} &0\\\dfrac{-1}{10}&\dfrac{1}{4}\end{bmatrix}[/tex]

Step-by-step explanation:

See jointed file

The inverse of the matrix A is

[tex]A = \left[\begin{array}{cc}-5&-2\\0&4\end{array}\right][/tex]

A matrix is a set of numbers arranges in rows and columns such that it form a rectangular array.

We have,

[tex]A = \left[\begin{array}{cc}-5&0\\-2&4\end{array}\right][/tex]

The matrix A is a square matrix and its determinant is not zero.

So the inverse exist.

The inverse of matrix A.

We will change the rows into columns and columns into rows.

So,

[tex]A = \left[\begin{array}{cc}-5&-2\\0&4\end{array}\right][/tex]

Thus,

The inverse of the matrix A is given above.

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Answer:

7/12

Step-by-step explanation:

3*4=12. 4/12+3/12=7/12.

Answer:

5/12

Step-by-step explanation:

you find the common factor of 12, divide 12 by the denominator, multiply the numerator by that, add the new numerators, put it on the denominator of 12, subtract it from 12/12

Answer:

x = 100°

Step-by-step explanation:

p and q are parallel lines. Construct line 'l' parallel to p and q

a = 30°   {p// l  when parallel lines are intersected by transversal alternate interior angles are congruent}

c +110 = 180  {linear pair}

c = 180  - 110

c = 70°

b= c   {q // l  when parallel lines are intersected by transversal alternate interior angles are congruent}

b = 70°

x = a + b

x = 30° + 70°

x = 100°

Answer:

y=4x/5-44/5

Step-by-step explanation:

First, we know that we can write any linear equation in the form y=ax+b, where a is the slope. This means that y=(4/5)x+b. Now, it has the point (1, -8). Plugging in x=1 and y=-8 gives us -8=(4/5)+b, which means that b=-44/5. Plugging this in gives us y=(4/5)x-44/5. Hope it helped!

Answer: Sheldon has made 50 cookies

Step-by-step explanation: for the first test because there are 5 rows and 4 cookies on each row you would multiply 4 times 5. That equals 20. The first tray has twenty and all trays are the same size so if the second one is completely full then it also has twenty. The third one is only half way full meaning twenty divided by two equals ten. Ten is the amount of cookies on the third tray. If you add that all together that is 20+20+10=50

The number of cookies made by Sheldon will be equal to 50.

The four basic mathematical operations are the addition, subtraction, multiplication, and division of two or even more integers. Among them is the examination of integers, particularly the order of actions, which is crucial for all other mathematical topics, including algebra, data organization, and geometry.

For the first test, you would multiply 4 by 5 because there are 5 rows and 4 cookies on each row. 20 is the result.

Since all trays are the same size and the first tray has twenty, if the second tray is totally filled, it will also have twenty.

Twenty divided by two equals 10 because the third one is only half full.

There are ten cookies on the third tray.

The total is,

20+20+10 = 50.

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9514 1404 393

Answer:

  D.  180°

Step-by-step explanation:

The letter S is symmetrical about its center. The letter looks the same when it is rotated 180° about its center.

Answer:

D

Step-by-step explanation:

Let's say that we have x amount of hours.

Casey addresses 22 envelopes per hour. Another way of writing this is that for x hours, Casey addresses 22 envelopes. Therefore, given x hours, Casey addresses 22 * x envelopes.

Anne can address 48 envelopes in 2 hours. It is important to note that this is for 2 hours. To make this per 1 hour, we can write

48 envelopes = 2 hours

divide both sides by 2

24 envelopes = 1 hour.

Therefore, given x hours, Anne addresses 24 * x envelopes.

Paula can address 62 envelopes in 3 hours, so

62 envelopes = 3 hours

divide both sides by 3

62/3 envelopes = 1 hour

Given x hours, Paula can address 62/3 * x envelopes.

Adding all of these up, given x hours, the group of friends can address

22 * x + 24 * x + 62/3 * x envelopes. Because the variables are all the same (x), we can add up the coefficients, resulting in

(22 + 24 + 62/3) * x = (46 + 62/3) * x envelopes given x hours

We want to figure out the amount of hours (x) for 420 envelopes. The total amount of envelopes is equal to (46 + 62/3) * x, so we set 420 equal to that, resulting in

(46 + 62/3) * x = 420

divide both sides by (46 + 62/3) to isolate x

420 / (46 + 62/3) = x

= 6.3 hours

Step-by-step explanation:

you're going to solve for y in the first equation and then substitute it in for the second equation and solve.

Answer:

8 lb box

Step-by-step explanation:

Find which laundry detergent has a lower unit price

The unit price is how much something costs for a single unit

In this case, it is how much the detergent costs for 1 pound

7.4/8 lbs = 0.925 dollars per lb

5.38/4 lbs = 1.345 dollars per lb

Since 1.345 > 0.925, the 8 lb box is a better buy

Case 1

Cost of 8 pound detergent = $7.40

So, cost of 1 pound detergent

= $7.40 ÷ 8

= $0.925

Case 2

Cost of 8 pound detergent = $5.38

So, cost of 1 pound detergent

= $5.38 ÷ 4

= $1.345

$0.925 < $1.345

$0.925 < $1.345So, cost per pound in 8 pound box < cost per pound in 4 pound box

So, buying the 8 pound box is better.

9514 1404 393

Answer:

  a) 11 cm

  b) 20 cm

Step-by-step explanation:

A square has four equal-length sides, so the perimeter is 4 times the side length. Then the side length is 1/4 of the perimeter.

  a) s = (1/4)(44 cm) = 11 cm

  b) s = (1/4)(80 cm) = 20 cm

Answer:

The answer is C. [tex]256\pi[/tex] [tex]in^2[/tex].

Step-by-step explanation:

To solve for the surface area of this cylinder, start by using the cylinder surface area formula, which is [tex]SA=2\pi rh+2\pi r^{2}[/tex]. Next, plug in the information given from the problem into the formula, which will look like [tex]SA=(2)(\pi )(8in)(8in)+(2)(\pi )(8in^{2})[/tex]. Then, simplify the equation, which will look like [tex]SA=(128in)(\pi) +(128in)(\pi)[/tex]. The next step is to simplify the equation further, which will look like [tex]SA= 256\pi[/tex] [tex]in^{2}[/tex]. The final answer is [tex]256 \pi[/tex] [tex]in^2[/tex].

Answer:

15 / 1

hope that helps uh...☺

Answer:

ab+bc+ac=47

Step-by-step explanation:

(a+b+c)=12

Square both sides

a^2+b^2+c^2+2(ab+bc+ac)=144

2(ab+bc+ac)=94

ab+bc+ac=47

Answer:

ab + bc + ca = 47

Step-by-step explanation:

Using the algebraic identity

(a + b + c) = a² + b² + c² + 2(ab + bc + ca) , then

12² = 50 + 2(ab + bc + ca)

144 = 50 + 2(ab + bc + ca) ← subtract 50 from both sides

94 = 2(ab + bc + ca) ← divide both sides by 2

47 = ab + bc + ca

Answer: g(x) = (1/2)3^-x  reflection over y axis yields (-x,y)

Answer:

4

Step-by-step explanation:

Answer:

B

Step-by-step explanation:

b/c the figure is right angle

Answer:

[tex]x = \frac{83}{7} [/tex]

Step-by-step explanation:

5x+(2x+7)=90

7x+7=90

7x=90-7

7x=83

x=83/7

x=11.857

Answer:

50

Step-by-step explanation:

The sum of interior angles in a triangle is equal to 180 degrees

since one of the angle is given as 80 the remaining is 100

The given is an isosceles triangle which means two of its side length and so its angles are equal in measure so 100/2 = 50

Answer:

4/5 t

Step-by-step explanation:

why?

80%xt by definition of p%=p/100

80/100t

80/100t reduce the fraction with 20

so the answer is;

4/5 t

Hope it helps

Answer:

A number line going from negative 1 to positive 7. Points are at positive 1 and positive 7.

Step-by-step explanation:

We have the equation:

|8 - 2*p| = 6

Remember that the equation:

|f(x)| = A

with A > 0

means that:

f(x) = A

or

f(x) = -A

Then for our case, we can rewrite:

|8 - 2*p| = 6

as:

(8 - 2*p) = 6

or

(8 - 2*p) = -6

Now we can solve these two equations to find the two possible values of p.

From the first one, we get:

8 - 2*p = 6

8 - 6 = 2*p

2 = 2*p

2/2 = p = 1

so one solution is  p = 1

Now from the other equation, we can get the other solution:

(8 -2*p) = -6

8 - 2*p = -6

8 + 6 = 2*p

14 = 2*p

14/2 = p = 7

So the two solutions are p = 1 and p = 7

Then the correct option is:

"A number line going from negative 1 to positive 7. Points are at positive 1 and positive 7."

Answer:

≈ 5.51 hours

Equation: 4.25h + 10

The number of hours Amanda rented the bike is 5.5 hours.

The equation used to solve this problem is 33.38 = 10 + 4.25h.

The rent cost for the helmet is $10.

The rent cost for the bike per hour is $4.25.

We need to find the number of hours Amanda rented the bike as she paid $33.38 in total.

We also have to make an equation that would solve this problem.

Consider h = number of hours Amanda rented the bike.

The cost for renting the helmet = $10.

And rent cost for the bike per hour = $4.25.

Amanda's total cost = Helmet rent cost + bike rent cost

Since we do not know the number of hours the bike was rented we will denote bike rent cost  = $4.25 x h

We have,

$33.38 = $10 + $4.25 x h

33.38 = 10 + 4.25 x h

33.38 - 10 = 4.25 x h

23.38 = 4.25 x h

h = 23.38 / 4.25

h = 5.5011

Rounding to the nearest tenths we get,

h = 5.5 hours

The number of hours Amanda rented the bike is 5.5 hours.

The equation used to solve this problem is 33.38 = 10 + 4.25h.

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